Optical-disk-mode pattern of InGaP microdisks emitting at 0.65 μm

Abstract

We report our study on the optical properties and the disk mode pattern of InGaP microdisks. The semiconductor InGaP microdisks with radius of about 5 micrometers emitting at wavelength of 0.65 micrometers were fabricated on liquid phase epitaxial grown InGaP/AlGaAs/GaAs wafer on the substrate of (100)GaAs. The optical properties of InGaP microdisks were studied by photoluminescence, pump-probe femtosecond- transient reflectivity measurements. The strong enhancement of the PL intensity in the microdisks respect to that of the same un-patterned epitaxial wafer is obtained. In addition, the inhibition effect of the microdisks on the ultrafast decay of optical excited carriers is observed by the transient measurement. The fluorescence image of the InGaP microdisk is analyzed by a CCD fluorescence microscope system. Under the green light excitation, a bright red ring of fluorescence near the edge of microdisk is observed. The typical fluorescence intensity profiles as a function of radius in different microdisks are plotted out. As a result, the images reveal the optical disk mode pattern in our InGaP microdisks dominated by Whispering-Gallery modes and mixture with other modes.